Platinum base alloy and spark plug electrode



Patented Dec. 16, 1947 PLATINUM BASE ALLOY AND SPARK PLUG ELECTRODE Franz R. Hensel, Indianapolis, Ind., assignor to P. R. Mallory & (30., Inc., Indianapolis, Ind., a

corporation of Delaware No Drawing. Application July 1, 1944, Serial No. 543,193

2 Claims. I (Cl. 75172) This invention relates to platinum base alloys and electrodes made therefrom.

An object of the invention is to improve such.

alloys and electrodes.

Platinum-molybdenum alloys have been proposed for spark plug electrodes. Such alloys are relatively hard and resistant to deflection at high temperatures. Moreover they remain bright and untarnished when heated in air. However, they are somewhat subject to grain growth and this becomes more marked when the electrode is fused directly into the ceramic of the spark plug.

I have found that this grain growth can be inhibited and an electrode material produced which remains fine grained even after continued heating by the addition of thorium.

The alloy and electrode material of the present invention may have the following composition:

Per cent Thorium .05 to 3 Molybdenum- .5 to 10 Platinum Balance 2 may be welded to the end of a nickel rod. One specific composition which is suitable for spark plug electrodes consists of Per cent Thorium Molybdenum -i- 4 Platinum 95.5

molybdenum and the balance platinum, said thorium serving to inhibit grain growth in said electrode.

FRANZ R. HENSEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,872,065 Duffenback Aug. 16, 1932 2,344,597 Chaston et a1. Mar. 21, 1944 1,948,445 Lederer Feb. 20, 1934 

